The present invention relates to video quality of service, and more particularly to a method of locating a point of interest in an impaired image using an impairment measurement map.
A video signal, after going through one or more iterations of video processing, such as compression, decompression, etc., may display perceptible impairments to a viewer. Part of determining video quality of service is to measure the amount of the impairment of the video signal. This is done using various impairment models, but most commonly used are PSNR and/or the human vision system model. This model generally takes the impaired video signal and compares it with an identical reference video signal that has not gone through the video processing, using an instrument such as the Tektronix PQA200 Picture Quality Analyzer. What is produced is a perceptual difference or impairment map representing subjective errors in the impaired video signal. The displayed intensity variations in the impairment map represent measurement values on a pixel-by-pixel basis. To determine where in the impaired video signal the points of interest represented by the impairment map are located requires some means for comparing the two images. This may be done by displaying the two images sequentially or side-by-side to provide a visual approximation.
What is needed is a means for easily locating or co-locating the point of interest in an impaired video signal corresponding to impairments represented by an impairment map for the impaired video signal.